Early performance of cement-based grouting material with silica fume.
Keywords: grouting material; silica fume; fluidity; early performance
Through adding different dosage of silica fume, studied the early performance of cement-based grout. Experiment result showed that mixing certain amount of silica fume can improve the grout fluidity and improve the grout surface state, thereby increasing grout groutability and compactness, and can also significantly improve the grout flexural strength and compressive strength. when silica fume was 2%,1d and 3d flexural strength increased by 43% and 22%,1d and 3d compressive strength increased by 50% and 73% compared with grout without silica fume.
Cement-based grouting material is an inorganic cementitious material used in building grouting. Its preparation principle is mainly based on dense packing theory, so the ultrafine particles (silica fume) fill the gap between large particles (cement particles) (large particles and small particles are generally 1-2 orders of magnitude different), so that the air attack of the material It is reduced to a minimum and reaches a high uniform density to improve the properties of the material. Replacing part of the cement with silica fume can increase the strength and increase the density.
When the amount of silica fume increased from 0 to 20%, the flexural strength and compressive strength of the grouting material increased first and then decreased with the increase of the amount of silica fume.when the silica fume content was 2%, the 1d and 3d flexural strengths increased by 43% and 22%, respectively, and the compressive strength increased by 50% and 73%, respectively, compared with the undoped silica fume. When the silica fume content exceeds 10%, it is lower than the strength of the undoped silica fume. After adding silica fume to the grouting material, the silica in the silica fume reacts with the hydrate of the cement to form calcium silicate with better stability and higher strength.
- When the proper amount of silica fume is added to improve the fluidity, when the silica fume is added with 4%-7%, the fluidity of the grouting material reaches 310mm, which is 3% higher than that without doping.
- Adding proper amount of silica fume can improve the surface state of the grouting material, reduce the formation of cheongsam, and increase the compactness.
- Adding proper amount of silica fume can improve the early flexural strength and compressive strength of the grouting material.